Flexible connector cable

Abstract

A flexible connector cable for providing high density and reliable electrical interconnections between printed circuit boards or any other surfaces having conductive paths that need connection to conductive paths on adjacent surfaces. The connector cable comprises a flat flexible laminar structure including an electrically-insulative layer and an electrically-conductive layer. The insulative layer is typically formed on a bonded plastic such as Polyimide and the conductive layer is typically formed of copper. Openings are formed in the insulative layer to expose the conductive layer and raised contacts or buttons are deposited on the conductive layer on both surfaces of the cable. The raised contacts are formed of ductile conductive material which exhibits plastic deformation under pressure to form good electrical connections.

The embodiments of the invention in which an exclusive property or privilege is claimed are described as follows: 
     
       1. An interconnection cable useful for electrically connecting to multiple points on a substantially-planar circuit board, said cable comprising: a flat flexible laminar structure including first and second material layers bonded to one another;   said first material layer being formed of a flexible electrically-insulative material;   said second material layer being formed of a thin flexible layer of electrically-conductive material;   said second material layer including an electrically continuious ground plane portion and one or more circuit path portions each physically spaced and electrically isolated from said ground plane portion and from each other circuit path portion, said ground plane and circuit path portions being physically configured so that each circuit path portion forms an island substantially surrounded by but electrically isolated from said ground plane portion;   first raised contacts formed of electrically-conductive material deposited on each of said circuit path portions remote from said first material layer;   said first material layer having voids formed therein to expose portions of said second material layer therethrough; and   second raised contacts formed of electrically-conductive material deposited on said exposed portions of said second material layer.   
     
     
       2. The cable of claim 1 wherein at least one of said first raised contacts is positioned in alignment with one of said second raised contacts. 
     
     
       3. The cable of claim 1 wherein said first raised contacts are formed of a ductile material capable of exhibiting plastic deformation when forced against said circuit board. 
     
     
       4. The cable of claim 1 wherein each of said first raised contacts is aligned with one of said second raised contacts; and wherein said raised contacts are formed of a ductile material capable of exhibiting plastic deformation when forced against a circuit board.   
     
     
       5. A cable structure useful for forming an electrical connection to a circuit path on a substantially-planar surface, said cable structure comprising: first and second substantially flat contiguous coextensive layers, said first layer being formed of flexible electrically-insulative material having opposite first and second substantially planar surfaces, said second layer being formed of flexible electrically-conductive material having a first planar surface bonded to said first layer first planar surface;   said second layer including a first electrically continuous portion and one or more second portions each physically spaced and electrically isolated from said first portion and from each other second portion, said first and second portions being physically configured so that each second portion forms an island substantially surrounded by but electrically isolated from said first portion;   at least one raised contact formed of electrically-conductive material deposited on each of said second layer second portions on the surface thereof remote from said first layer, each such raised contact being formed of a material more ductile than said second layer whereby said contact will exhibit plastic deformation in response to a force applied thereto essentially normal to said second layer;   said first layer including voids therein exposing said second layer therethrough; and   at least one raised contact formed of electrically-conductive material deposited on the portion of said second layer exposed through said first layer voids.   
     
     
       6. The structure of claim 5 wherein said raised contact deposited on said exposed portion of said second layer is aligned with a raised contact deposited on said second layer second surface to thereby produce a through-connection through said cable. 
     
     
       7. The structure of claim 5 wherein said second layer is formed of copper. 
     
     
       8. The structure of claim 5 wherein said first layer is formed of Polyimide.